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[摘要]：The reactions of dianionic C-60 with organic halides, which have been studied extensively in benzonitrile (PhCN), are revisited in a different solvent medium, N,N-dimethylformamide (DMF), by using ArCH2Br (Ar = Ph, C6H4CH3, C6H4Br). Interestingly, instead of the 1,4-R2C60 adducts, which are the typical products when the reactions are carried out in PhCN, the 1,2-dihydro[60]fullerenes (1,2-HRC60) have been obtained as the major products in DMF, except for the case of o-CH3C6H4CH2Br probably due to the steric effect. The obtained 1,2-dihydro[60]fullerenes have been characterized with single-crystal diffraction, H-1 and C-13 NMR, high-resolution mass spectrometry (HRMS), and UV-vis. Further examination with deuterated reagents including PliCD(2)Br, DMF-d(7), and D2O has revealed that the fullerenyl hydrogen of 1,2-dihydrofullerenes originates from traces of water residue in DMF. When the reaction is re-examined in PhCN with the addition of an excessive amount of water, the yield of 1,2-dihydrofullerene increases significantly, but is still lower compared with that obtained in DM F, demonstrating a considerable solvent effect on the reactivity of C-60(2-). A possible mechanism accounting for such a difference is proposed. The work has presented an alternative protocol for effective preparation of 1,2-dihydro[60]fullerenes, and may also provide clues toward a better understanding of the proton transfer process for anionic Coo-mediated reducing, reactions involving H2O. |
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